System and method for broadband isolated output

Abstract

The invention relates to a system and method for broadband isolated output. An apparatus includes a first output of a first radio frequency (RF) signal. An apparatus includes a second output of a second RF signal. The device includes a first transistor having a first source / drain. The device includes a second transistor having a first source / drain, wherein the first source / drain of the first transistor is coupled to the first source / drain of the second transistor and wherein the first transistor and the second transistor are disposed between the first output and the second output.

Description

Technical Field

[0001] The present disclosure generally relates to systems and methods for signal amplification and transmission. In particular, the present disclosure relates to an output circuit that can be used with an amplification circuit, such as a radio frequency (RF) amplifier. Background Art

[0002] Over the past few decades, the wireless communication device market has grown by orders of magnitude, driven by the use of portable devices and the increase in connectivity and data transfer between various devices. Digital switching technology has promoted the large-scale deployment of affordable, easy-to-use wireless communication networks. In addition, improvements in digital and radio frequency (RF) circuit manufacturing and advances in circuit integration and other aspects have made wireless devices smaller, cheaper and more reliable. Wireless communication can operate according to various standards, such as IEEE 802.11x, Bluetooth, Global System for Mobile Communications (GSM) and Code Division Multiple Access (CDMA). With the development of higher data throughput, network density and other changes, newer standards are constantly being developed for adoption. Many devices may include multi-device radios, antennas or other components. Such multi-mode devices can operate across various protocols, power levels, frequencies, etc. Summary of the invention

[0003] In one aspect, the present disclosure provides a device comprising: a first output of a first radio frequency (RF) signal; a second output of a second RF signal; a first transistor having a first source / drain; and a second transistor having a first source / drain, wherein the first source / drain of the first transistor is coupled to the first source / drain of the second transistor and wherein the first transistor and the second transistor are disposed between the first output and the second output.

[0004] In another aspect, the present disclosure provides a system comprising: an amplifier comprising: a first output for a first radio frequency (RF) signal; and a second output for a second RF signal; and a cascode circuit comprising: a first source / drain of a first transistor coupled to the first output; and a first source / drain of a second transistor coupled to the second output; and a first source / drain of a third transistor coupled to a second source / drain of the first transistor and a second source / drain of the second transistor.

[0005] On the other hand, the present disclosure provides a method comprising: receiving a first signal at a gate of a first transistor, the first signal comprising: a first content centered on a first frequency; and a second content centered on a second frequency; receiving the first content at a first source / drain of a second transistor; receiving the second content at a first source / drain of a third transistor, wherein the first content and the second content comprise radio frequency content; and the first frequency exceeds the second frequency by up to 1.5 GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The various objects, aspects, features and advantages of the present disclosure will become more apparent and better understood by referring to the detailed description taken in conjunction with the accompanying drawings, wherein the same reference numerals identify corresponding elements throughout the entire text. In the drawings, the same reference numerals generally indicate the same, functionally similar and / or structurally similar elements.

[0007] Figure 1 is a schematic block diagram of a radio frequency amplification circuit according to some embodiments.

[0008] Figure 2 is another schematic block diagram of a radio frequency amplification circuit according to some embodiments.

[0009] Figure 3 is a schematic block diagram of a radio frequency amplification circuit according to some embodiments, which depicts inter-port signal paths associated with the radio frequency amplification circuit.

[0010] Figure 4 is a flow chart illustrating the operation of a method according to some embodiments.

[0011] The details of various embodiments of the method and system are set forth in the accompanying drawings and the description below. DETAILED DESCRIPTION

[0012] The following disclosure provides many different embodiments or examples for implementing the different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the disclosure. Of course, these are merely examples and are not intended to be limiting. The disclosure may repeat reference numbers and / or letters in various examples. This repetition is for the purpose of brevity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0013] Some embodiments disclosed herein relate to a device. The device may include a first output of a first radio frequency (RF) signal. The device may include a second output of a second RF signal. The device may include a first transistor having a first source / drain. The device may include a second transistor having a first source / drain. The first source / drain of the first transistor may be coupled to the first source / drain of the second transistor. The first transistor and the second transistor may be disposed between the first output and the second output.

[0014] In some embodiments, an input of the device is coupled to a gate of a third transistor. A first source / drain of the third transistor may be coupled to the first source / drain of the first transistor and the first source / drain of the second transistor. In some embodiments, a second source / drain of the first transistor is coupled to a first terminal of a first conductor. A second terminal of the first conductor may be coupled to a first voltage. A second source / drain of the second transistor may be coupled to a first terminal of a second conductor. The second terminal of the second conductor may be coupled to the first voltage.

[0015] In some embodiments, the first source / drain of the first transistor and the first source / drain of the second transistor are coupled to a first source / drain of a third transistor. The first gate of the first transistor may be coupled to a first voltage. The second gate of the second transistor may be coupled to a second voltage. The second source / drain of the third transistor may be coupled to a third voltage. In some embodiments, the first voltage is different from the second voltage and the third voltage. In some embodiments, the second voltage is not different from the third voltage.

[0016] In some embodiments, the first output includes a first T-filter configured to preferentially pass the first RF signal to a first connection terminal. The second output may include a second T-filter configured to preferentially pass the second RF signal to a second connection terminal. In some embodiments, a first parameter of the first T-filter is different from a second parameter of the second T-filter. In some embodiments, the magnitude of the isolation between the first connection terminal and the second connection terminal is -20 dB or greater at the following frequencies: a first center frequency of the first RF signal, and a second center frequency of the second RF signal.

[0017] In some embodiments, the first center frequency of the first RF signal differs from the second center frequency of the second RF signal by more than 1.5 GHz. In some embodiments, the first RF signal and the second RF signal are derived from the same antenna. In some embodiments, the first output and the second output are outputs of a power divider.

[0018] Some embodiments disclosed herein relate to a system. The system includes an amplifier. The amplifier may include a first output of a first radio frequency (RF) signal. The amplifier may include a second output of a second RF signal. The amplifier may include a cascode circuit. The cascode circuit may include a first source / drain of a first transistor coupled to the first output. The cascode circuit may include a first source / drain of a second transistor coupled to the second output. A first source / drain of a third transistor may be coupled to a second source / drain of the first transistor and a second source / drain of the second transistor.

[0019] In some embodiments, the first output includes a first T-filter configured to preferentially pass the first RF signal to the first connection terminal. The second output may include a second T-filter configured to preferentially pass the second RF signal to the second connection terminal. In some embodiments, the magnitude of the isolation between the first connection terminal and the second connection terminal is -20 dB or greater at the following frequencies: the first center frequency of the first RF signal, and the second center frequency of the second RF signal. In some embodiments, the first RF signal and the second RF signal are derived from the same antenna. In some embodiments, the first center frequency of the first RF signal differs from the second center frequency of the second RF signal by more than 1.5 GHz. In some embodiments, the first output includes a first T-filter configured to preferentially pass the first RF signal to the first connection terminal. The second output may include a second T-filter configured to preferentially pass the second RF signal to the second connection terminal. The first parameter of the first T-filter may be different from the second parameter of the second T-filter.

[0020] Some embodiments disclosed herein relate to a method. The method includes receiving a first signal at a gate of a first transistor. The first signal may include first content centered at a first frequency. The first signal may include second content centered at a second frequency. The method may include receiving the first content at a first source / drain of a second transistor. The method may include receiving the second content at a first source / drain of a third transistor. The first content and the second content may include radio frequency content. The first frequency may exceed the second frequency by up to 1.5 GHz.

[0021] In some embodiments, the method may include receiving a non-zero DC voltage at a second gate of the second transistor and a third gate of the third transistor.

[0022] An amplifier (e.g., a low noise amplifier for an RF circuit) may supply one or more output signals to one or more devices via corresponding output ports of the amplifier. For example, an antenna may receive signals of any number of communication protocols (e.g., Wi-Fi, cellular, Bluetooth, etc.) and provide the aggregated signal to the amplifier for amplification. The amplifier may generate outputs corresponding to various communication protocols, their frequency bands, or other signals. The output of the amplifier may receive interference or other signals, for example, via direct coupling from a device at the output, inductive coupling along a PCB trace, cabling, or other similar means. In addition, some outputs may contain different spectral content relative to other outputs. Achieving isolation between various output ports may avoid mutual interference, increase the signal-to-noise ratio of various output signals, or otherwise assist in the transmission of various output signals.

[0023] The cascode circuit at the output of the amplifier may include a common transistor for receiving a signal derived from a source such as an antenna. The cascode circuit may further include a separate second stage output (e.g., a separate transistor for each output) so that the signal path joining the various outputs can extend across the channel of its corresponding output transistor. Thus, isolation (e.g., -20 dB isolation) can be achieved between the various outputs. Isolation can be assisted by other elements of the separate output ports. For example, a pull-up network to VCC may include an inductive element to filter the RF signal between the various outputs. In addition, in the case where the various output ports include different frequencies (e.g., non-overlapping along at least a portion of the operation), the components of the filter of each output (or the inductive element of the pull-up network) can be selected to selectively pass the signal of the output relative to the other outputs.

[0024] For clarity of the present disclosure, before proceeding to further describe the systems and methods provided herein, an illustrative description of various terms is provided:

[0025] In some embodiments, the output of a device may refer to or include a port (e.g., a terminal) for an output signal generated by the device (e.g., converted by the device) or a terminal for providing an output signal. The output signal may include an amplified signal of an amplifier device. For example, a voltage or frequency may be amplified relative to an input signal along at least a portion of the spectrum. A terminal may refer to or include an element configured to couple a device to another device to transmit a signal. For example, an electrical terminal may include a conductive element electrically coupled to a device connected to an output (e.g., a power divider connected to one or more other outputs). To continue the example, an output terminal of a radio frequency (RF) signal may be configured to transmit a radio frequency signal. In some embodiments, a radio frequency (RF) signal may refer to or include a signal including one or more components within the RF range, which may extend from the kilohertz range to the GHz range (e.g., to hundreds of GHz). An RF signal may occupy a bandwidth spanning a frequency range. In some embodiments, the center frequency of a signal may refer to or include the midpoint of its spectrum. For example, a signal extending from 2,427 MHz to 2,447 MHz as associated with a center frequency of 2,437 MHz.

[0026] In some embodiments, the content of an RF signal may refer to or include encoded information. The encoded information may include symbols that can be parsed into digitally encoded data according to a predefined mapping. The RF signal may be derived from an antenna. In some embodiments, an antenna may refer to or include a device for receiving electromagnetic waves (e.g., RF signals).

[0027] In some embodiments, a power splitter may refer to or include a device that receives an input signal and generates two or more output signals. The output signals may have the same or different power, frequency range or other properties. The power splitter may include, for example, a Wilkinson splitter.

[0028] In some embodiments, a non-zero direct current (DC) voltage may refer to or include a DC voltage that is different from one or more ground levels (e.g., power ground, signal ground, chassis ground, etc.) This voltage may also be referred to as a bias voltage, and may be biased positively or negatively with respect to ground.

[0029] In some embodiments, isolation may refer to or include the degree to which output ports are decoupled from each other. For example, isolation may be quantified as a measure of the portion of one port that can be measured at another port. Greater isolation refers to ports that are more isolated (e.g., have a smaller magnitude of a signal that can be measured at another port) corresponding to a numerically smaller number. For example, two ports isolated at -30 dB exhibit greater isolation than two ports isolated at -20 dB.

[0030] According to some embodiments, a T-type filter may refer to or include a circuit having a series arm and a shunt arm. The series arm is usually depicted as the horizontal portion of the T-shaped piece, and the shunt arm is usually described as the vertical portion of the T-shaped piece. The series arm may include a capacitor, an inductor, or other filtering elements. The shunt arm may be connected along the series arm to connect to a voltage, such as a ground or bias voltage. According to some embodiments, the parameters of the T-type filter may refer to or include characteristic impedance, propagation speed, attenuation, phase shift, voltage standing wave ratio (VSWR), capacitors, inductors, resistance values, etc. In some embodiments, an inductor may refer to or include a component configured to store electrical energy in the form of a magnetic field to resist changes in the current when the current flows through it.

[0031] In some embodiments, preferentially passing may refer to or include a signal passing through a filter or another element with less attenuation than at least some other signals. For example, a filter may preferentially pass based on magnitude, frequency, phase, etc. To continue the example of frequency, a low pass filter may preferentially pass low frequency signals, a band pass filter may preferentially pass selected frequencies, and a high pass filter may preferentially pass high frequencies.

[0032] In some embodiments, a cascode circuit may refer to or include an amplifier circuit including at least two output stages. For example, a first output stage may be shared by two ports having an input at the gate, and a second stage may extend across a channel of a transistor coupled to the source / drain of the first output stage, the transistor being biased according to a reference voltage. In some embodiments, the source / drain of a transistor may refer to or include a terminal for receiving or providing a channel of current. In some embodiments, the gate of a transistor may refer to or include a terminal for controlling the flow of current through its channel. The gate may correspond to various transistor types, and it is not desirable to limit the operating region.

[0033] In some embodiments, a voltage node may refer to or include a point on a circuit where two or more circuit elements are connected together. For example, a power plane (e.g., a ground plane) and a connection between a passive or active component or between two or more passive or active components may be referred to as a voltage node.

[0034] Figure 1A schematic block diagram of a radio frequency amplification circuit 100 according to some embodiments is depicted. The circuit 100 may be configured to operate along various frequency bands. For example, the circuit 100 may operate across various frequency bands of a wireless protocol, such as a wireless fidelity (Wi-Fi) protocol, or across various wireless protocols, such as Wi-Fi, Bluetooth, etc. The circuit 100 may include a low noise amplifier 102, which is configured to receive a signal from an input port, such as an antenna 104. The signal may include content distributed across one or more channels, such as channels that exhibit spectrum diversity. For example, the antenna 104 may be a broadband antenna configured to receive various signals, such as Wi-Fi signals in a 5 or 6 GHz band (e.g., between 5.15 and 7.125 GHz), in a 2.4 GHz band (e.g., 2.4 to 2.5 GHz), or other signals, such as Bluetooth content (e.g., in the range of 2.4 to 2.49 GHz), cellular phone signals, etc.

[0035] The amplifier 102 may output a signal to one or more devices (or terminals configured to connect to other devices). For example, the amplifier 102 may be coupled to a splitter 106 to connect to multiple devices 108, or to transmit multiple frequency bands or signals to a single device 108. The difference in operating frequency between the devices 108 may be extended beyond other approaches, such as greater than 1.5 GHz to operate using the 5 GHz and 6 GHz Wi-Fi bands, or greater than 4 GHz to operate using other 2.4 GHz bands for Wi-Fi or Bluetooth systems. The circuit 100 may be implemented on or include one or more silicon dies, multi-die packages, circuit boards, etc.

[0036] The antenna 104 may receive various incidental signals or interference, such as wireless transmissions from radar systems, cordless phones, power line interference (e.g., 50 or 60 Hz), etc. The filter (e.g., the depicted notch filter 110) may be configured to pass a band-select frequency range corresponding to the bandwidth of the amplifier 102. According to the frequency response of the notch filter 110, the input impedance 112 to the amplifier 102 may vary with frequency. For the frequency of interest, the notch filter may be adjusted to increase the input impedance. However, the adjustment may target a center frequency of operation, where broadband operation may exceed the rejection band of the notch filter 110. The separator 106 (e.g., a power divider) may include inter-output isolation between the broadband outputs.

[0037] Reference Figure 2, according to some embodiments, another schematic block diagram of a radio frequency amplifier circuit 100 is provided. The schematic block diagram is provided as a functional schematic diagram and is not necessarily associated with the physical placement of any particular component. In addition, although particular components are referred to as components of an amplifier or outputs associated therewith, such classifications are merely descriptive according to the depictions provided herein. For example, although a dashed line is provided as a boundary of the amplifier 102, this depiction is not limiting. The portion of the circuit outside the boundary line may be referred to as outputs of the amplifier 102 / outputs for the amplifier 102 or another component (e.g., Figure 1 106 (e.g., an RF power splitter). For example, in some examples, the depicted circuit 100 may be referred to as an amplifier 102. As depicted, the amplifier 102 may include a common transistor 202, which is depicted as a first stage of one or more cascode circuits. A first source / drain of the common transistor 202 is connected to a reference voltage 220, which is depicted as ground. In various embodiments, the reference voltage 220 may include various other voltage levels, such as to bias the output of the circuit 100 upward or downward. A second source / drain of the common transistor is connected to any number of outputs of the circuit 100. For example, the depicted circuit includes two outputs.

[0038] The cascode circuit includes a common transistor 202 and any number of other transistors separating the second stage. The common transistor 202 receives an input signal at its gate and provides an amplified output signal to the first source / drain of any number of cascode devices in the second stage of the cascode circuit. The common transistor 202 may amplify more or less than the second stage (e.g., one of the first stage or the second stage may be unity gain for one or more outputs). The various cascode devices of the second stage may include a feedback network (not depicted) at one terminal and to a voltage node (which includes the second source / drain of the associated transistor 212, 214), a terminal of a pull-up network associated with the output (e.g., its inductor 216, 218), and a portion of a transmission line filter associated with the output.

[0039] The depicted circuit 100 includes a cascode device including a first transistor 212 corresponding to a first output and a second transistor 214 corresponding to a second output. The first source / drain of the first transistor 212 and the second transistor 214 are connected to each other at the second source / drain of the common transistor 202. The first output and the second output depicted as extending to or extending through the first transmission line 206 and the second transmission line 210 (e.g., the distal end or proximal end thereof) can be connected to one or more devices, or configured to preferentially pass some signals relative to other signals. For example, the outputs 206, 210 can be configured to pass signals with different frequencies, power levels, magnitudes, or other attributes according to their filters. The gates of the first transistor 212 and the second transistor 214 can be coupled to different or, as depicted, the same bias voltage 222 to control their outputs at the respective second source / drain. In addition, the voltage node of the bias voltage 222 can be VCC or a reference voltage 220, or another voltage.

[0040] The respective outputs may be connected to one or more devices 108 (e.g., first device 108A and second device 108B, as depicted). Devices 108 may be coupled to the depicted circuit 100 through terminals (e.g., pins, balls, bumps, posts, etc.) of a semiconductor device, a printed circuit board connection, or an on-chip connection. For example, the connection may be in a metallization layer formed on an active surface of a semiconductor die, the active surface including an n-well or p-well for the depicted transistor, or otherwise including one or more of the components of the depicted circuit 100.

[0041] The first output is provided between the amplifier 102 and the first device 108A. The first output extends from the second source / drain of the common transistor 202 to the first transmission line 206. The first output includes a first transistor 212 connected to a first voltage 224 (e.g., VCC) through a pull-up network including an inductive element 216 (e.g., an RF choke). The power plane for the first voltage can provide RF isolation (e.g., to improve isolation between the first output and the second output) by attenuating any RF signals.

[0042] A second output 208 is provided between the amplifier 102 and the second device 108B. The second output extends from a second source / drain of the common transistor 202 to a second transmission line 210. The second output 208 includes a second transistor 214 connected to a voltage, which may be the same voltage as the first voltage 224 (e.g., VCC), or may be different therefrom.

[0043] In various embodiments, the circuit may include a third, fourth, fifth, or other output arranged in parallel with the depicted output. For example, the other outputs may include other second-stage transistors of other cascode circuits coupled to the second source / drain of the common transistor 202, pull-up networks, gate biases, etc. The other (or depicted) outputs may include components that are the same between the various outputs or vary according to power level, frequency, output device, etc. For example, the output may include various bias voltages according to the required power level of the output, pull-up networks according to the required isolation or frequency response, various cascode device sizes, or different transmission lines 206, 210 according to the required frequency band associated with the signal. The various outputs may be configured to operate using signals with different frequencies (e.g., center frequencies in the case of a combination of one or more Wi-Fi, Bluetooth, cellular, or other protocols). Some frequencies may include various communication protocol channels that vary between 900MHz, 2.4GHz, 5GHz, 6GHz, etc. That is, the center frequencies of the various signals may vary by more than 1GHz, such as 1.5GHz, 2GHz, 4GHz, etc. Furthermore, the various outputs may be coupled to other devices, which may couple various signals (e.g., interfering signals) into the outputs such that isolating the outputs may improve bit rate error, throughput, or other characteristics of circuit 100 or a network that includes circuit 100. For example, the various outputs may be connected via cables, conductive traces, or other connectors, which may be coupled directly or inductively into the outputs (e.g., along signal conductors, shields, etc.).

[0044] Figure 3 is another schematic block diagram of a radio frequency amplification circuit 100 according to some embodiments. The schematic block diagram includes a signal path 302 between a first terminal 304 of a first output and a second terminal 306 of a second output. The signal path 302 is provided as a non-directional path. According to various embodiments, the isolation of the path may be directional, so that the isolation from the first output to the second output (sometimes referred to as the S23 transmission coefficient (corresponding to the second and third ports of the circuit)) is different from the isolation from the second output to the first output (e.g., the S32 transmission coefficient).

[0045] The signal path may vary depending on component values ​​associated with the output, the frequency of the signal associated with the output, etc. The depicted signal path 302 is not intended to depict the only signal path. For example, other signal paths may extend through feedback networks, power planes (e.g., through corresponding pull-up networks, their inductive elements 216, 218, etc.). However, depending on some component values ​​or noise rejection of the power or ground planes, particularly for frequencies in the GHz range, the depicted signal path 302 may constitute a significant portion (e.g., a majority) of the isolation between output channels.

[0046] In addition, in order to depict the propagation of the signal path 302 through the circuit 100, some example transmission line components are depicted. In particular, the first transmission line 206 and the second transmission line 210 are depicted as including T-shaped filters, which include respective shunt arms to a reference voltage 220, which may be common or different between the transmission lines of the various outputs. For example, as depicted, the reference voltage 220 may be ground, which is shared with the reference voltage 220 of the first source / drain of the common transistor 202. The shunt arms include respective inductive elements 308, 310. The terminals of the respective inductive elements 308, 310 opposite the reference voltage 220 are connected to the connected terminals of the series capacitors of the transmission lines 206, 210. For example, the inductive element 308 of the first output may be connected to a near-end capacitor 312 and a far-end capacitor 314 relative to the amplifier 102. The inductive element 310 of the second output may be connected to a near-end capacitor 316 and a far-end capacitor 318 relative to the amplifier 102.

[0047] Although the signal path 302 is set to be non-directional as described above, for ease of description only, the signal path may be described as starting from the first terminal 304. The signal path 302 extends across the first transmission line 206 (e.g., the series arm of its T-type filter). The signal path 302 extends across the channel of the first transistor 212 to a node including the first source / drain of the second-stage cascode transistor (e.g., the first transistor 212 and the second transistor 214). The signal path 302 extends across the channel of the second transistor 214 to the second transmission line 210, and across its series arm (e.g., capacitors 316, 318).

[0048] The passage across multiple transistor channels can substantially limit the flow of any incidental parts between the outputs, so that the S23 or S32 isolation can substantially isolate the outputs. For example, the isolation can exceed -20 dB (e.g., according to the depicted signal path 302 in combination with any other signal paths). For example, the isolation between the center frequencies of the respective output signals associated with the first terminal 304 and the second terminal 306 can exceed -20 dB. The T-filter can selectively pass signals according to the resonant frequency.

[0049]

[0050] For example, for a resonant frequency of 6 GHz (e.g., corresponding to a frequency band of 5 to 7 GHz), the capacitor of the first output may be approximately 1 pF, and the inductor may be approximately 7 nH. Of course, this value is a first-order approximation of the circuit performance, which will vary depending on geometry, input impedance (e.g., into first transistor 212, second transistor 214, first device 108A, second device 108B, etc.), any parasitic resistances, etc. (which can be readily determined based on various RF simulation techniques).

[0051] Thus, a T-filter (or other transmission line network employed in various embodiments) may be configured to selectively pass RF signals associated therewith, which may further aid isolation by both limiting the attenuation of desired signals and increasing the attenuation of other (e.g., aggressor) signals across the transmission line. For example, any parameter of a T-filter or other transmission line may be different from any other transmission line. For example, selected component values, circuit geometry, or other variations may be configured to affect such parameters.

[0052] Circuit 100 may isolate signals, such as signals derived from the same antenna, so that separate signals may be provided to different ports (e.g., relative to the output port of amplifier 102) with isolation therebetween. That is, circuit 100 may be or include a power splitter configured to separate a signal received from antenna 104 into various component signals, each component signal being configured to be provided to a separate amplifier output that may be connected to any number of devices.

[0053] Figure 4 is a flow chart showing the operation of a circuit operation method 400 according to some embodiments. In operation 402, a transistor (eg, Figure 2 and Figure 3 The signal may include any number of constituent signals, such as signals of various frequencies, protocols, durations, and the like. For example, in the case of 2.4 GHz Wi-Fi and Bluetooth messages, Wi-Fi messages that overlap basic service sets, and the like, a portion of the constituent signals may overlap in frequency or duration. The signal may be received from an antenna and passed through any number of filters, splitters, rectifiers, or other circuit systems. A portion of the constituent signals may include content, such as symbols mapped to digital information. For example, the received signal may include first content centered around a first frequency (e.g., a first center frequency). The received signal may include second content centered around a second frequency (e.g., a second center frequency).

[0054] At operation 404, the first content is received at another transistor (e.g., at its source / drain). For example, a signal may propagate from the gate of the common transistor 202 to amplify its magnitude as an output at the source / drain of the common transistor 202. The output may be connected to the source / drain of a transistor (e.g., the first transistor 212 of the first output). The first content may be received along with other content (e.g., the second content, the third content, etc.), which may include signals associated with the device connected to the output, interference, or other signals. The transistor (e.g., the first transistor 212) may pass the first content across its channel based on the non-zero DC voltage received at the gate to provide to the first device (e.g., across a first T-shaped filter corresponding to the first content).

[0055] In operation 406, the second content is received at another transistor (e.g., at its source / drain). For example, the transistors of operation 404 and operation 406 may be a separate second stage of a cascode circuit and any number of other transistors. The center frequency of the second content may vary by more than 1.5 GHz, 2 GHz, 4 GHz, or another value relative to the center frequency of the first content. The second content may include information encoded according to the same or different protocol relative to the first content. A transistor (e.g., second transistor 214) may pass the second content across its channel to provide to a second device (e.g., across a second T-filter corresponding to the second content) based on a non-zero DC voltage received at the gate that may be the same or different from the voltage received at the gate of the transistor of operation 404. For example, the first and second T-filters may vary according to their parameters.

[0056] References to "or" may be interpreted as inclusive, such that any term described using "or" may indicate any of a single, more than one, and all of the described terms. References to at least one of a conjunction list of terms may be interpreted as inclusive or to indicate any of a single, more than one, and all of the described terms. For example, reference to "at least one of 'A' and 'B'" may include only 'A', only 'B', and both 'A' and 'B'. Such references used in conjunction with "includes" or other open terms may include additional items.

[0057] It should be noted that certain paragraphs of the present disclosure may refer to terms (e.g., "first" and "second") related to transmission spatial streams, sounding frames, responses, and subsets of devices for identification or distinction from each other or other purposes. These terms are not intended to relate entities (e.g., first device and second device) only in time or according to order, although in some cases, these entities may include such relationships. These terms also do not limit the number of possible entities (e.g., reader elements, writer elements, or magnetic media) that can operate within a system or environment. It should be understood that the system described above may provide multiple of any one or each of the components, and these components may be set on a stand-alone machine, or in some embodiments, on multiple machines in a distributed system. Further, bit field positions may be changed, and multi-bit words may be used. In addition, the systems and methods described above may be provided as one or more computer-readable programs or executable instructions embodied on or in one or more articles of manufacture (e.g., floppy disks, hard disks, CD-ROMs, flash memory cards, PROMs, RAMs, ROMs, or tapes). The program may be implemented in any programming language (e.g., LISP, PERl, C, C++, C#) or in any bytecode language (e.g., JAVA). The software program or executable instructions may be stored as object code on or in one or more articles of manufacture.

[0058] The term "coupled" and its variations include two components directly or indirectly joined to each other. The term "electrically coupled" and its variations include two components directly or indirectly joined to each other through a conductive material (e.g., a metal or copper trace). This joining may be static (e.g., permanent or fixed) or movable (e.g., removable or releasable). This joining may be achieved by two components being directly coupled to each other or directly coupled to each other, two components being coupled to each other using a separate intermediary component and any additional intermediate components that are coupled to each other, or two components being coupled to each other using an intermediary component that is integrally formed as a single entity with one of the two components. If "coupled" or its variations are modified by additional terms (e.g., directly coupled), the general definition of "coupled" provided above is modified by the ordinary language meaning of the additional terms (e.g., "directly coupled" means the joining of two components without any separate intermediary components), resulting in a definition that is narrower than the general definition of "coupled" provided above. This coupling may be mechanical, electrical (e.g., magnetic), or fluid.

[0059] Although the above written description of the methods and systems enables one of ordinary skill in the art to make and use embodiments thereof, one of ordinary skill in the art should understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiments, methods, and examples herein. Therefore, the methods and systems should not be limited to the above-described embodiments, methods, and examples, but should be limited to all embodiments and methods within the scope and spirit of the present disclosure.

Claims

1. A device comprising: a first output of a first radio frequency RF signal; a second output of a second RF signal; a first transistor having a first source / drain; and A second transistor having a first source / drain, wherein the first source / drain of the first transistor is coupled to the first source / drain of the second transistor and wherein the first transistor and the second transistor are disposed between the first output and the second output.

2. The apparatus of claim 1 , comprising an input coupled to: A gate of a third transistor, a first source / drain of the third transistor coupled with the first source / drain of the first transistor and the first source / drain of the second transistor.

3. The device according to claim 2, wherein: A second source / drain of the first transistor is coupled to a first terminal of a first conductor, a second terminal of the first conductor is coupled to a first voltage node; and A second source / drain of the second transistor is coupled to a first terminal of a second conductor, and the second terminal of the second conductor is coupled to the first voltage node.

4. The device according to claim 1, wherein: The first source / drain of the first transistor and the first source / drain of the second transistor are coupled to a first source / drain of a third transistor; A first gate of the first transistor is coupled to a first voltage node; A second gate of the second transistor is coupled to a second voltage node; and The second source / drain of the third transistor is coupled to a third voltage node.

5. The device according to claim 4, wherein: The voltage of the first voltage node is different from the voltage of the second voltage node and the voltage of the third voltage node.

6. The device according to claim 4, wherein: A voltage of the second voltage node is not different from a voltage of the third voltage node.

7. The device according to claim 2, wherein: The first output includes a first T-filter configured to preferentially pass the first RF signal to a first connection terminal; and The second output includes a second T-filter configured to preferentially pass the second RF signal to a second connection terminal. 8 . The apparatus of claim 7 , wherein a first parameter of the first T-filter is different from a second parameter of the second T-filter.

9. The device according to claim 7, wherein: The magnitude of the isolation between the first connection terminal and the second connection terminal is -20 dB or greater at the following frequencies: a first center frequency of the first RF signal; and a second center frequency of the second RF signal.

10. The device according to claim 1, wherein: A first center frequency of the first RF signal differs from a second center frequency of the second RF signal by more than 1.5 GHz.

11. The device according to claim 1, wherein: The first RF signal and the second RF signal are derived from the same antenna.

12. The device according to claim 1, wherein: The first output and the second output are outputs of a power divider.

13. A system comprising: An amplifier comprising: a first output of a first radio frequency RF signal; and a second output of a second RF signal; and A cascode circuit, comprising: a first source / drain of a first transistor coupled to the first output; and a first source / drain of a second transistor coupled to the second output; and The first source / drain of the third transistor is coupled with the second source / drain of the first transistor and the second source / drain of the second transistor.

14. The system of claim 13, wherein: The first output includes a first T-filter configured to preferentially pass the first RF signal to a first connection terminal; and The second output includes a second T-filter configured to preferentially pass the second RF signal to a second connection terminal.

15. The system of claim 14, wherein: The magnitude of the isolation between the first connection terminal and the second connection terminal is -20 dB or greater at the following frequencies: a first center frequency of the first RF signal; and a second center frequency of the second RF signal.

16. The system of claim 13, wherein the first RF signal and the second RF signal are derived from the same antenna.

17. The system of claim 13, wherein a first center frequency of the first RF signal differs from a second center frequency of the second RF signal by more than 1.5 GHz.

18. The system of claim 13, wherein: The first output includes a first T-filter configured to preferentially pass the first RF signal to a first connection terminal; and The second output comprises a second T-filter configured to preferentially pass the second RF signal to a second connection terminal, wherein: A first parameter of the first T-type filter is different from a second parameter of the second T-type filter.

19. A method comprising: A first signal is received at a gate of a first transistor, the first signal comprising: first content centered on a first frequency; and a second content centered on a second frequency; receiving the first content at a first source / drain of a second transistor; The second content is received at a first source / drain of a third transistor, wherein The first content and the second content include radio frequency content; and The first frequency exceeds the second frequency by 1.5 GHz.

20. The method according to claim 19, comprising: A non-zero DC voltage is received at the second gate of the second transistor and the third gate of the third transistor.

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